NF-kappaB inhibits gammaherpesvirus lytic replication. – PubMed

Real-time monitoring of M3FL infection revealed novel sites of viral replication, such as salivary glands, as well as acute replication in the nose and the lung and progression to the spleen. Here, we report significant differences in MHV-68 infection in the two species: (i) following intranasal inoculation, MHV-68 replicated in the lungs of wood mice to levels approximately 3 log units lower than in BALB/c mice; (ii) in BALB/c mice, virus replication in alveolar epithelial cells was accompanied by a diffuse, T-cell-dominated interstitial pneumonitis, whereas in wood mice it was restricted to focal granulomatous infiltrations; (iii) within wood mice, latently infected lymphocytes were abundant in inducible bronchus-associated lymphoid tissue that was not apparent in BALB/c mice; (iv) splenic latency was established in both species, but well-delineated secondary follicles with germinal centers were present in wood mice, while only poorly delineated follicles were seen in BALB/c mice; and, perhaps as a consequence, (v) production of neutralizing antibody was significantly higher in wood mice. RNA obtained from an MHV-68 latently infected cell line, from cells lytically infected with MHV-68 in culture, and from the lung tissue of infected mice was used to probe the MHV-68 arrays. The infected cells are therefore poorly recognized by the host immune system, allowing the virus to persist for long periods of time. Available data support a model in which gammaherpesvirus infection drives B cell proliferation and differentiation. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. Incorporation of this mutation into MHV68 yielded a virus with significantly reduced capacity for mRNA turnover.

GHV are highly species-specific, and suitable animal models for EBV are not available. RNA obtained from an MHV-68 latently infected cell line, from cells lytically infected with MHV-68 in culture, and from the lung tissue of infected mice was used to probe the MHV-68 arrays. To this end, we cloned the MHV-68 genome as a bacterial artificial chromosome (BAC) in Escherichia coli. Shabman et al. Here we report the generation and in vivo characterization of a recombinant murine gammaherpesvirus 68 (gammaHV68) that expresses a constitutively active form of the NF-kappaB inhibitor, IkappaBalphaM. This study has, for the first time, characterized EBV infection in neural cell backgrounds by using the Sh-Sy5y neuroblastoma cell line, teratocarcinoma Ntera2 neurons, and primary human fetal neurons. Herpesvirus virions are surrounded by a lipid envelope that contains numerous glycoproteins that mediate entry into the cell.

MHV68 infection of mice provides a highly useful system to dissect the function of specific viral elements in the context of both asymptomatic infection and disease. The GC content of the unique portion of the genome is 46%, while the GC content of the terminal repeat is 78%. The infected cells are therefore poorly recognized by the host immune system, allowing the virus to persist for long periods of time. To this end, we cloned the MHV-68 genome as a bacterial artificial chromosome (BAC) inEscherichia coli. Here, we demonstrate that IFN-γ is a powerful inhibitor of reactivation of γHV68 from latency in tissue culture. Thus, recurrent infection of these developing B cell populations could allow the virus continual access to the B cell lineage and, subsequent to differentiation, the memory B cell compartment. However, latent virus in peritoneal cells and splenocytes from IFN-alpha/betaR(-/-) mice reactivated ex vivo with >40-fold- and 5-fold-enhanced efficiency, respectively, compared to wt cells.

The impact of the inflammasome response on gammaherpesvirus replication and latency in vivo is not known. To address this issue, we investigated the pathogenesis of murine herpesvirus 68 (MHV-68) infection in mice deficient in CD4 or CD8 T-cell populations. We show that γHV68 infection leads to significant splenic B-cell proliferation as late as day 42 postinfection. Here we demonstrate that the gammaHV68 latency-associated M2 protein has a cell-type-dependent localization pattern: M2 is present in the cytoplasm and plasma membrane in lymphocytes, whereas it is present primarily in the nucleus in epithelial and fibroblast cells. These viruses can be subdivided into two genera: lymphocryptoviruses (gamma-1) and rhadinoviruses (gamma-2) (Fig. Murid herpesvirus 4 (MuHV-4), which realistically infects inbred mice, provides a useful tool with which to understand further how a γHV colonizes B cells in vivo. MHV68 infection of mice provides a highly useful system to dissect the function of specific viral elements in the context of both asymptomatic infection and disease.

The number of amino acid changes can be determined using the scale shown at the bottom of the tree. Genes missing from these blocks are designated as ΔS below- the black rectangles. Notably, this acute, lethal pneumonia was dependent not only on the viral dose, but also on specific viral genes including the viral cyclin gene, previously identified to be important in promoting optimal chronic infection and reactivation from latency. Four kinetic classes of transcripts were observed following infection of 3T3 cells: immediate-early (K3, Rta, M8, and ORF73), early (DNA pol), early-late (M3, M11, and ORF74), and late (M2, M9, and gB).